Hall-effect measurements of metalorganic vapor-phase epitaxy-grown p-type homoepitaxial GaN layers with various Mg concentrations

Mg-doped p-type gallium nitride (GaN) layers with doping concentrations in the range from 6.5 x 10(16)cm(-3) (lightly doped) to 3.8 x 10(19)cm(-3) (heavily doped) were investigated by Hall-effect measurement for the analysis of hole concentration and mobility. p-GaN was homoepitaxially grown on a GaN free-standing substrate by metalorganic vapor-phase epitaxy. The threading dislocation density of p-GaN was 4 x 10(6)cm(-2) measured by cathodoluminescence mapping. Hall-effect measurements of p-GaN were carried out at a temperature in the range from 130 to 450 K. For the lightly doped p-GaN, the acceptor concentration of 7.0 x 10(16)cm(-3) and the donor concentration of 3.2 x 10(16)cm(-3) were obtained, where the compensation ratio was 46%. We also obtained the depth of the Mg acceptor level to be 220meV. The hole mobilities of 86, 31, 14cm(2)V(-1) 1 s(-1) 1 at 200, 300, 400 K, respectively, were observed in the lightly doped p-GaN. (C) 2017 The Japan Society of Applied Physics